The present invention relates to lamination-type piezoelectric transformers.
In general, the piezoelectric transformer is constructed of a sheet of a piezoelectric member 2 as shown in FIG. 9 and a drive part 2a at an input side is polarized in the direction of thickness, and a power generation part 2b at an output side is polarized in the direction of length. When alternating voltage of the direction of thickness is applied between electrode patterns 4 and 6 at the input side, a vertical vibration occurs in the direction of length in the piezoelectric member 2. The alternating voltage is generated at the power generating part 2b of the piezoelectric member 2 by the vertical vibration, and the alternating voltage is fetched from the output terminal.
The conventional piezoelectric transformers utilize only the one side of a drive unit at the input side, and do not utilize the other side. As a result, such conventional piezoelectric transformers cannot fetch the large electric current efficiently from the output side.
A primary object of the present invention is to fetch multiple outputs efficiently by utilizing both sides of the piezoelectric member at the primary side, and to solve the foregoing problems.
The above-noted piezoelectric transformer is called the Rosen type piezoelectric transformer, and is unfit for power generation due to low drive frequency and high internal impedance.
Another object of the present invention is to provide a piezoelectric transformer suitable for power generation with a small internal impedance which produces a high frequency with utilization of the thickness vertical vibration.
Furthermore, another object of the present invention is to provide a piezoelectric transformer that transmits the vertical vibration at the primary side to the secondary side efficiently and which produces a plurality of outputs efficiently with an input and which provides a large electric current from the output side.
The present invention is to fetch multiple outputs efficiently by utilizing both surfaces of the piezoelectric member at the primary side.
The primary piezoelectric member is polarized in the direction of thickness or in the direction of length. The secondary side piezoelectric members, which are polarized in the direction of thickness or in the direction of length, are laminated at both sides ofthe direction of thickness or length of the primary piezoelectric member. When alternating voltage is applied to an input terminal at the primary side, thickness vertical vibration occurs in the primary side piezoelectric member by a piezoelectric counter effect, which is a kind of mechanical vibration. The vertical vibration propagating in the direction of thickness is propagated to the secondary side piezoelectric member, and an alternating voltage is generated by positive effect of piezoelectricity on the secondary side piezoelectric member and this alternating voltage is transferred to the first output terminal and the second output terminal.